asteroid misses earth

An asteroid up to twice the size of the one that levelled the forest of Tunguska, Siberia, has just whizzed perilously close to the Earth.

The rock, which is known as 2008/9 DD45 and is estimated to be between 20 and 50 metres across, passed just 72,000 kilometres above the Earth on Monday. That's less than one fifth of the distance from here to the moon.

The asteroid, named 2009 DD45, was discovered just Friday by Australian astronomers. Had it hit the Earth, it would have exploded with the force of a large nuclear blast. That’s not very reassuring when you consider humans had only three days’ notice. The asteroid is likely to be drawn in by Earth’s gravity, meaning it may return many times in the future. Let’s hope that humanity is as lucky then as we were today.

The asteroid passed the Earth at a distance of 46,000 miles, a near miss in terms of cosmic distances. Though asteroid 2009 DD45 was just about two hundred feet long, it might have impacted with the force of a nuclear blast.

Astronomers are comparing asteroid 2009 DD45 to the rock that caused the Tunguska impact of 1908. The 1908 impact occurred in Siberia near the Tunguska River and destroyed the taiga forest at a distance of twenty five kilometers around the epicenter. The Tunguska impact, which was technically an air burst explosion rather than a ground collision, had the force of a multi-megaton nuclear blast. Had asteroid 2009 DD45 hit a populated area, such as a large city, it would have laid it waste. Had asteroid 2009 DD45 hit the ocean it would have caused a tsunami that would have devastated coastlines.

Astronomers suggest that asteroid 2009 DD45 is now in a solar orbit that intersects the Earth's orbit. That means that asteroid 2009 DD45 will be visiting the vicinity of Earth again.

The near miss of 2009 DD45, which was detected just two or so days before it passed the Earth, illustrates the continuing danger that the Earth faces due to asteroid impacts. Asteroid 2009 DD45 suggests that not only greater efforts should be made to detect and track such asteroids before they become a threat, but strategies should be put into place to divert them should they be found to be on a collision course.

An asteroid 2.5 to 6 miles in length impacted the Earth near the Yucatan 65 million years ago. The Yucatan impact threw up unimaginable amounts of water vapor, dust, and other debris, blotting out the sun for years. It is thought to have rendered most life on Earth, including the dinosaurs, extinct. A similar impact in current times would certainly end human civilization and likely the human species.

Take a look at the video of 2008 DD45 narrowly avoiding a devastating collision with life as we know it after the jump.